2GJ 



DISCOVERY 



Magnetic car has been on the American market for 

 some time, and the Entz transmission system has been 

 employed with success on some American battleships. 

 Nevertheless, its commercial application to the propul- 

 sion of road vehicles is a new thing over here, and it is 

 from this point of view that I am undertaking this 

 description for readers of Discovery. 



To give a full and detailed description of every 

 component of the system in its practically applied form 

 would mean writing a small volume, and consequently 

 this account of the Crown Magnetic car must be re- 

 garded as a compromise between a technical description 

 of the leading chassis features and a full exposition 

 of the working of the transmission system. I want to 

 make it clear to the best of my ability just how this 

 transmission system operates, and merely to avoid a 

 charge of obvious incompleteness I intend to refer 

 first — though more or less casually — to such features 

 of the car as would interest the motorist as such. 



Enclosed under the bonnet and behind the radiator 

 of conventional design is an ordinary, although large, 

 petrol engine, this having six cylinders with a bore and 

 stroke of 102 x 140 mm., giving a nominal horse-power 

 output of 38, although, of course, the actual output 

 is much in excess of this, for the engine is constructed 

 on the most up-to-date lines and has the overhead 



THE CROWN MAGNETIC STEERING WHEEL, SHOWING THE 

 VARIOUS POSITIONS FOR THE CONTROLLING SWITCH. 



valves which have become so popular on car engines 

 as the result of aero experience during the war. The 

 springing of the car is conventional, being by semi- 

 elliptic springs all round ; and combined with the com- 

 paratively high weight of the vehicle, some 2 J tons, 

 ensures perfect comfort for the occupants over all types 

 of roads. Detachable wheels and electric lighting and 

 starting complete the equipment. And now to deal 

 with its transmission system. 



Firstly, let us be quite clear that we understand the 



working of the electric dynamo and motor. An ordin- 

 ary dynamo used for the generation of current consists 

 of a set of electric magnets between the pole pieces of 

 which revolves an armature, i.e. a soft iron core wound 

 with insulated wire. This armature is by some 

 mechanical means revolved on its longitudinal axis 

 between the pole pieces of the magnets, and this 

 revolution and the consequent cutting of the lines of 

 magnetic force from the magnets by the windings of 

 the armature are the immediate cause of the generation 

 of current. Other things take place, of course. There 

 is, for instance, the building up of the current, as it is 

 known, foras soon as the armature begins to revolve, the 

 magnetism of the magnet is increased and armature 

 and magnets work together to give the desired result 

 of a high-current output. These further details, how- 

 ever, are beside our present purpose. WTiat I want to 

 be perfectly clear is that the generation of current 

 depends on the revolution of the armature inside the 

 magnets, in other words, on the difference in speed 

 between the two components. From the purely 

 electrical point of view it would not matter whether 

 the armature were revolved mechanically inside the 

 magnets or the magnets were revolved mechanically 

 outside the armature. The same difference in speed 

 would be present, and we should have the same result 

 of the generation of electric current. 



To go a step further, suppose we had the two neces- 

 sary components of a dynamo mounted in correct 

 relation to each other and together mounted as a 

 single unit on a pedestal in such a manner that both 

 components were free to revolve. If we now turn 

 either the armature or the magnetos by mechanical 

 means the second component will follow the one that is 

 revolved, through the action of what is known as 

 magnetic drag. In other words, there will be no differ- 

 ence in speed and there will be no generation of current. 

 So far, so good, and now for the motor. In essentials 

 of construction the electric motor is the same as a 

 dynamo, but instead of one component being operated 

 by mechanical means, current is fed, usually to the 

 magnets, and the armature is thus given a rotary 

 motion by magnetic attraction. In the dj-namo, then, 

 we apply mechanical energy and take out electrical, 

 in the motor we apply electrical energy and take out 

 mechanical. With this great difference the two units 

 are the same, and the remarks above as to the re- 

 lativity between the actions of armature and magnet 

 apply to the motor just as they do to the dynamo. 

 Here we have, then, the principles of the Entz trans- 

 mission in a nutshell, and we can now proceed to a 

 description of its practical application on the Crown 

 Magnetic car. 



Extending forwards from the back a.\le, which is of 

 normal construction, is a propeller shaft as in any car 



